of defective drilled shafts shall be the responsibility of the Contractor and shall be at no cost to the Division . After the concrete level has reached the required top elevation, it shall be forced to overflow in the case of tremie or pump placement, leaving only fresh, uncontaminated concrete. In the case of placement by free fall (dry conditions), the concrete shall be continued high enough to compensate for any settlement due to removal of casing. The top ten (10) feet of each rock socketed drilled shaft shall be vibrated except when more than ten (10) feet is to be exposed above the ground line or the riverbed/streambed, then the entire exposed portion shall be vibrated. The concrete shall not be vibrated until after any temporary casing is removed. Exposed portions of each rock socketed drilled shaft shall be cured in accordance with Section 601.12.
625.6.4 -Removal of Casing: Removal of the casing from a shaft may occur gradually as concrete is placed. Insofar as possible, casing extraction shall be done at a slow uniform rate by application of a steady vertical upward pull in the direction of the axis of the shaft. To facilitate extraction , tapping on the casing, exertion of temporary downward pressure, slight rotation, or the controlled use of a vibratory hammer will be permitted, but care must be taken to avoid harmful impacts or disturbances to th e fresh concrete. Vibration or rodding may not be used to break the casing loose for extraction. If, during extraction of casing, upward movement of concrete and/or reinforcing steel occurs, the Engineer shall be notified immediately. If the Engineer c onsiders the movement to be minor, then the extraction of the casing may continue. If, however, the movement is deemed significant and indicative of squeezing of the surrounding soil thus resulting in a reduction of the drilled shaft diameter, then the En gineer may order the casing to be left in place, or permit extraction to proceed and order a later non -destructive load test, or may order other procedures as appropriate at no additional cost to the Division. For the upper portions of rock socketed dril led shafts that will be exposed and visible, the casing may remain in place as a form until the concrete has attained a strength that enables it to stand alone without further deformation. Casing shall then be removed.
625.7 -INSPECTION OF SOCKETS : 625.7.1 -Inspection: The Engineer will inspect the shaft as outlined in subsections 625.7.2.4 and 625.7.2.5 . Time required for inspection will be considered incidental to the work and will not be cause for extra compensation related to a claim or extension of contract time.
625.7.2 -Division Testing: 625.7.2.1 -Preinstallation Core Holes: The Cont ractor shall provide notice to the Technical Support Division via e -mail (DOHDrilledShafts@wv.gov ) when each site is ready for drilling. The Division will commence drilling of the preinstallation core hole within 5 working days after notification from Contractor that site has suitable access for drilling. A preinstallation test boring will be drilled by the Division at each rock socketed drilled shaft location, or as shown on the plans, to determine the character of the material that the rock socketed drilled shaft extends through and the material that is at the base of the shaft in order to ensure the material along and below the tip of the rock socket is capable of carrying the load that will be imposed on it. The preinstallation borings are to be drilled prior t o beginning excavation for each representative rock socketed drilled shaft. The Contractor shall provide all work necessary to allow access for the drill rig to the
496 preinstallation test boring location, which at a minimum shall include constructing drill pads and access roads. Unless otherwise directed, the preinstallation test borings are to be extended a minimum depth of two ( 2) upper drilled shaft diameters but not less than ten (10) feet below the planned tip elevation of the rock socketed drilled shaft shown on the plans. Standard Penetration Testing (SPT) and sampling shall be performed at five ( 5) foot intervals in the preinstallation borings in accordance with AASHTO T 206. Roc k coring will be performed in accordance with ASTM D2113 using a wireline core barrel system and will commence immediately upon obtaining an SPT value of 50 blows per six (6) inches or less on bedrock. The recovered core sample size will be approximately two ( 2) inch diameter (NX or NQ size). Additional preinstallation test borings in other locations may be required where directed by the Engineer. Test boring logs of each preinstallation boring will be prepared by the Division and will be provided to the Contractor within three ( 3) working days of completion of the test boring. The preinstallation test borings logs will describe the type and thickn ess of all soil and rock layers, and locate the presence of groundwater, open joints, voids, soft rock, or other deleterious material. All recovered soil and rock samples shall be maintained by the Division and stored on site at suitable location, provide d by the Contractor, until completion of the project. Within 10 working days after completion of preinstallation core hole, the Engineer will notify the Cont ractor of the final tip elevations for each drilled shaft location.
625.7.2.2 -Wet or Dry Hole De termination: The Division will check the depth of water at the bottom of the drilled shaft. If the depth does not increase by more than twelve (12) inches over a 1 -hour period, the hole will be considered dry. Otherwise, the hole will be considered wet.
625.7.2.3 -Plumbness: Contractor shall provide notice to the Technical Support
each drilled shaft will be ready for inspection. Plumbness of the rock socketed drilled shaft/rock socket shall be measured by the Division by measuring the geometry of the drilled shaft excavation using SHAPE, Sonicaliper, or other suitable means. For any rock socketed drilled shaft, the maximum permissible deviation from plumb shall be 1.5% measured with respect to the vertical axis at the center of the drilled shaft excavation. The Contractor shall provide suitable access and means for lowering inspection equipment into the drilled shaft excavation. For any rock socketed drilled shaft at its top, the maximum deviation of the center shall be three ( 3) inches from its project plan location. The maximum deviation of the f inished top of shaft from the plan elevation shall be minus one (1) inch or plus three ( 3) inches. An absolute minimum cover of three ( 3) inches to the reinforcing steel is strictly required. In the event of any deviations in the dimensional requirements , the contractor shall not proceed with construction of pier columns or cap until submission and approval of a corrective plan has been granted.
625.7.2.4 -Rock Sock Sidewall Inspection: Contractor shall provide notice to the Technical Support Division v ia e-mail ( DOHDrilledShafts@wv.gov ) five ( 5) working days